Micro-ElectroMechanical Systems (MEMS) are known and in use for sensors, accelerometers, and gas chromatographs. A MEMS device may be used as a switch to interrupt or allow propagation of a signal, and/or to hold an on and/or an off position. A MEMS switch may require application of external energy (e.g., a voltage source) to be bi-stable. Mostly these switches fall in to either ohmic and/or capacitive in nature categories. Alternatively, a minima MEMS switch may use local minima of mechanical energy in a structure to hold a bi-stable position. But all these devices may require a large structure size. In addition, these MEMS devices may consume a large amount of energy and/or have switching times greater than an acceptable threshold time. These switches may therefore not compete with current devices used to store computer memory.
A probe MEMS device may address data by positioning a storage media with respect to an array of sharp probe tips. In order to scan data stored on a media plate, however, this MEMS device may require a large array of probe tip read/write heads, which may add a substantial cost and/or complexity to the memory device. This cost and complexity may prevent the probe MEMS device from competing with commercially available memory devices.
Alternatively, bi-stability can be achieved through surface adhesion and/or modification. A MEMS device may be comprised of a floating beam that may be switched between an open and closed state. The memory device may require an adhesion (e.g., a stiction, a surface tension, etc.) to hold a memory element in a stable position. The adhesion may be unpredictable and/or have varying strengths. The adhesion may be lower than a threshold strength needed to hold the memory element after one use and/or after repeated use, and/or the adhesion may allow the physical structure to disconnect from a surface once a switching force is released. Alternatively, the adhesion may be greater than a threshold strength that will permit the memory element to move after it has been bonded to the surface, preventing the memory device from being used more than once. The unpredictability of such device may limit its practical utility in commercial usage.